Spraying device

ABSTRACT

An improved air spraying device for spraying a liquid having self cleaning means including a stem adapted to move into and out of the spray outlet without interrupting the continuous flow of air and liquid, the stem being normally biased out of said outlet.

ited States Patent 51 Aug. 22, 1972 Diegelman [s41 SPRAYING DEV ICE [72] Inventor: Fredrick Henry Diegelman,

Whiteford, Md.

[73] Assignee: Bethlehem Steel Corporation 22 Filed: 16, 1970 21 Appl. No.: 98,651

[52] US. Cl ..239/1 18, 239/296 [51] Int. Cl. ..B05b 15/02 [58] Field of Search ..239/104, 113, 114, 117,118, 239/8 [56] References Cited UNITED STATES PATENTS 3,198,435 8/1965 Ullman,....'..., ..239/l17 Primary Examiner-Lloyd L. King Assistant ExaminerThomas C. Culp, Jr. Attorney-Joseph J. OKeefe ABSTRACT An improved air spraying device for spraying a liquid having self cleaning means including a stem adapted to move into and out of the spray outlet without interrupting the continuous flow of air and liquid, the stem being normally biased out of said outlet.

4'Clains, 5 Drawing Figures 1 SPRAYING DEVICE BACKGROUND OF THE INVENTION coating or layer of protective paintonto the surface of the article. Included in these protective paints are some '15 and 16, and pneumatic control panel. The

very heavy paints, as e.g., inorganic zinc paint which,

' because of the nature of the paint, causes frequent clogging at points where the paint particles can settle out from the vehicle and form a thick hard residue. The paint must be agitated and a continuous and even flow maintained through the spraying devices with the excess being returned to the supply tank.

Spraying devices of the prior art may include a stem adapted to clean the spray outlet. However, the stem actsas a means to stop the flow of material through the outlet. In addition the stem may also interrupt the flow of air through the device. Such stoppage or interruption frequently results in clogging of the 'spraying device by allowing the spraying material to partially solidify. Thus it is necessary to stop the spraying operation and clean the cloggedspraying device. When spraying heavy paints, e.g., inorganic zinc paints, the spraying system must be completely purged when clogging occurs to insure against additional clogging. Obviously, such clogging adversely affects the efficiency of the spraying operation.

It is an object of this invention to provide a spraying device adapted to maintain a continuous flow of material therethrough to minimize clogging.

It is another object of this invention to provide a device having an automatic intermittently operated self-cleaning feature while maintaining a continuous flow of material through the device.

SUMMARY OF THE INVENTION The instant invention accomplishes these objects by providing a spraying device comprising a stem adapted to'move into and out of the spray discharge outlet without interrupting the continuous flow of air and liquid through the device. In addition the stem is normally biased out of the discharge outlet to further insure a continuous flow of spraying material through the device.

BRIEF DESCRIPTION OF THE DRAWINGS tional view similar to FIG. 2 showing the discharge outlet cleaning means in the operative position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings for a detailed description of the invention and particularly to FIG. 1. The schematic arrangement of paint spraying equipment is seen to generally comprise a pair of reciprocators l0 and 11 on opposite sides of a workpiece W, paint tank 12, pumps 13 and 14, paint supply lines (solid lines),

reciprocators 10 and 11 are provided with a series of interconnecting spraying devices which are removably mounted on the reciprocators in varying numbers as required for the particular workpiece. FIG. 1 shows reciprocator 10 provided with three spray devices 20 while its opposite number 11 is provided with only two spray devices 20. The spray devices 20 are provided with paint supplied by pumps 13 and 14 from tank 12 and atomizing air under controlled pressure from the pneumatic control panel. The mixture of atomizing air and paint at the nozzle creates the spray for coating the workpiece W as is well understood by those skilled in the art. The reciprocators 10 and 11 traveling in unison are moved by conventional means back and forth across the workpiece W depositing a full coating on the workpiece W as it passes between the spraying devices 20. The reciprocators l0 and 11 cause the trip valves 15 and 16 to be actuated at the end of each forward stroke. The trip valves 15 and 16 being thus actuated cause a surge of fluid to be injected into a portion of each of the spraying devices 20 simultaneously to project a cleaning element through the paint discharge outlet, thus cleaning out any build up of heavy residue at that point, as hereinafter described.

The plurality of valves, regulators, fittings and circuitous piping present in prior art equipment is noticeably absent in the spraying equipment herein described.

The plurality of spraying devices 20 which are mounted on the reciprocators 10 and 11 are arranged in groups of 3 and 2 respectively as vhereinbefore described. The devices 20 are connected to insure a continuous flow of paint from the tank 12 through the devices 20 and back to the tank by way of the return lines. It will be apparentfrom a subsequent detailed description of the spraying device 20 that this flow of paint is continuous even though the discharge outlet 23 of a device 20 may become clogged.

. Referring now to FIGS. 2 and 3, the spraying device 20 generally comprises a body 21; a nozzle portion 24; a first chamber 22 at one end of the body 21 including an open or unobstructed passageway terminating in a first outlet 23 in nozzle 24 for spraying material; a second chamber 25 for atomizing air and including an open or unobstructed passageway through body member 21 and terminating in a plurality of second outlets 29 in the nozzle 24 adjacent the spraying material outlet 23; and a third chamber 30 on the body 21 opposite the outlet 23. Inlet 26, FIG. 3, is provided to supply paint or other spraying material to the first chamber 22. Outlet 27 is also provided opposite the inlet 26 as seen in FIG. 3 to allow the continual flow of spraying material through the body 21 of the spraying device 20 even when there is an obstruction closing the outlet 23. Air under pressure is supplied through inlet 28 into air chamber 25 where it is distributed to outlets 29 in nozzle 24 to atomize the paint or other spraying material discharged from outlet 23.

The third chamber 30 is located at the back end of the body 21 opposite the outlet 23 and includes an end wall 31 and a closure cap 32. A stem 33 having a pointed end 34 for projection through outlet 23 for the purpose of clearing any residue therefrom extends rearwardly from the outlet 23 through chamber 25 and into the chamber 30 where an enlarged portion of the stem is attached to a piston 36 which is slidably mounted within the chamber 30. The pointed end 34 of the stem 33 is adapted to pass through the outlet 23 with clearance between the stem and the outlet thereby permitting a diminished but continual flow of material therethrough. Spring means as e.g., a compression spring 35 is mounted with chamber 30 surrounding stem 33 with one end in contact with chamber end wall 31 and the other end contacting one side of the slidably mounted piston 36 to normally bias the stem 33 away from the outlet 23. Piston 36 is adjustable on stem 31 so that the clearance between the opening of the discharge outlet 23 and the pointed end 34 can be regulated to prevent interference with the flow of spraying material to the nozzle outlet 23. A rear portion 37 of chamber 30 is created by a boss 38 on the underside of closure cap 32 extending into chamber 30 to form a stop for the rearward movement of piston 36. Inlet 39 is provided in rear portion 37 of chamber 30 to allow fluid under pressure to be introduced, when desired, to act upon the piston 36 to force the piston and thus the stem 33 forward against the compression spring 35 projecting the pointed end 34 of stem 33 through the paint discharge outlet 23. Any build up of paint residue at the outlet will be effectively dislodged and forced outward leaving a clear opening in the outlet 23 upon return of the piston and stem to its rearward position. As seen in FIGS. 4 and 4a when the cleaning stem is in its forward or operative position the pointed end 34 does not obstruct the flow of material through the outlet 23 or in the chamber 22 adjacent outlet 23. In addition the guide shoulder 43 on the rear portion of the stem 33 does not obstruct the flow of air in air chamber 25. The forward movement of the stem 33 is limited by gland nut 44. Adjusting nut 40 in closure cap 32 provides ad ditional adjusting means for positioning the pointed end 34 of stem 33 with respect to the opening it is designed to clean and further provides a means of adjusting the compression of spring 35 against piston 36.

The spraying devices 20 are adapted to be mounted on reciprocators l and 11 in the number and fashion required for spraying a particular workpiece as mentioned hereinbefore. The body portion 21 is provided with an aperture 41 therethrough to receive a reciprocator mounting rod (not shown) and set screw 42 for fixing the position of the device on the rod.

In operation: Pumps 13 and 14 supply paint to the plurality of spraying devices 20. Reciprocators l0 and 11 positioned opposite one another with a conveyor (not shown) between them are provided with spraying devices 20 usually in groups depending on the size and shape of the workpiece W to be spray coated. The spraying devices 20 of each respective group are connected together in series. A single source of spraying material paint tank 12, provides the material for all of the spraying devices with each group having separate pump means. As seen in FIG. 1, pump 13 supplies the spraying material to the spray devices 20 on reciprocator through paint supply lines. The excess paint passes through all the devices and is returned to the paint tank 12 through discharge lines as shown, thus maintaining a continuous flow of material through the system. The spray devices on reciprocator 11 are supplied in similar manner. An agitator (not shown) is provided in the tank to continually agitate the paint to maintain a thorough mixing of the paint components. The reciprocators 10 and 11 are adapted to move in unison back and forth across the conveyor to spray the workpiece W. As the reciprocators 10 and l I reach the forward limit of their travel trip valves 15 and 16 are actuated which in turn actuates the piston 36 in the spraying device 20 to project the cleaning stem 33 through the paint discharge outlet 23 at the nozzle end 24 of the device 20. The trip valves 15 and 16 are immediately closed as the reciprocators 10 and 11 start their return cycle across the workpiece W and the action of compression spring 35 against the piston 36 retracts the cleaning stem 33. The cleaning action of stem 33 is only milliseconds in duration. Thus, an intermittent automatic cleaning cycle is provided. The arrangement of the devices 20 permits the continual flow of spraying material through the devices 20 with the excess material returned to the supply tank 12. Atomizing air under controlled pressure is continuously supplied to the nozzle 24 to combine with the spraying material to form the spray that coats the workpiece W. Sprayed thickness is controlled by the speed of the reciprocators and the size of the outlets 23 and 29.

lclaim:

1. In a spraying device comprising a body member, a first chamber in said body member having a continually open first outlet for spraying material, a second chamber in said body member having a second outlet for air adjacent said first outlet, the improvement comprising:

a. a third chamber in said body member aligned with and spaced from said first outlet,

b. a stem slidably mounted in said body member having one end extending within said third chamber and the other end extending within said first chamber, said other end shaped to pass through said first outlet,

c. first means in said third chamber to move said other end of said stem through said first outlet, and

\ d. second means in said third chamber to normally bias said other end of said stem to a position removed from said first outlet.

2. The device according to claim 1 wherein the means of subparagraph (d) is a spring loaded piston slidably mounted in said third chamber.

3. A spraying device comprising:

a. a body member,

b. a first chamber including an open passageway through said body member and terminating in a first outlet,

c. a second chamber including an open passageway through said body member and terminating in a plurality of second outlets adjacent said first outlet,

d. a third chamber in said body member,

e. a stem slidably mounted in said body member having one end extending within said third chamber, an intermediate portion extending within said second chamber and the other end extending within said first chamber, said other end shaped to pass through said first outlet,

f. a piston slidably mounted in said third chamber and attached to said one end of said stem,

5 v 6 g. means to normally bias said other end of said stem paragraph (g) includes to a position removed from said first outlet and to i. a spring in contact with one side of said piston and move said piston within said third chamber and a anepd Wall ftbird chamber, and said other end of said stem through said first outan Inlet Said chamber to PPR Y a mild under l pressure to the other side of said piston. 4. The device of claim 3 wherein the means of sub- 

1. In a spraying device comprising a body member, a first chamber in said body member having a continually open first outlet for spraying material, a second chamber in said body member having a second outlet for air adjacent said first outlet, the improvement comprising: a. a third chamber in said body member aligned with and spaced from said first outlet, b. a stem slidably mounted in said body member having one end extending within said third chamber and the other end extending within said first chamber, said other end shaped to pass through said first outlet, c. first means in said third chamber to move said other end of said stem through said first outlet, and d. second means in said third chamber to normally bias said other end of said stem to a position removed from said first outlet.
 2. The device according to claim 1 wherein the means of subparagraph (d) is a spring loaded piston slidably mounted in said third chamber.
 3. A spraying device comprising: a. a body member, b. a first chamber including an open passageway through said body member and terminating in a first outlet, c. a second chamber including an open passageway through said body member and terminating in a plurality of second outlets adjacent said first outlet, d. a third chamber in said body member, e. a stem slidably mounted in said body member having one end extending within said third chamber, an intermediate portion extending within said second chamber and the other end extending within said first chamber, said other end shaped to pass through said first outlet, f. a piston slidably mounted in said third chamber and attached to said one end of said stem, g. means to normally bias said other end of said stem to a position removed from said first outlet and to move said piston within said third chamber and said other end of said stem through said first outlet.
 4. The device of claim 3 wherein the means of subparagraph (g) includes i. a spring in contact with one side of said piston and an end wall of said third chamber, and ii. an inlet to said chamber to supply a fluid under pressure to the other side of said piston. 